Powder Seal Assembly for Decreasing Powder Usage in a Powder Bed Additive Manufacturing Process

ABSTRACT

An additive manufacturing machine for repairing a component includes a build platform that supports the component and a powder dispensing assembly for selectively depositing additive powder over the build platform. A powder seal assembly includes a powder support plate positioned above the build platform and defining an aperture for receiving the component without contacting the component. A clamping mechanism is movable relative to the powder support plate and defines a void for receiving a resilient sealing element around the aperture. An actuating mechanism, such as bolts or a linear actuator, moves the clamping mechanism toward the powder support plate to deform the resilient sealing element until the resilient sealing element contacts and forms a seal with the component.

FIELD

The present subject matter relates generally to additive manufacturingmachines, and more particularly to powder seal assemblies for decreasingpowder usage in a powder bed additive manufacturing process.

BACKGROUND

Machine or device components frequently experience damage, wear, and/ordegradation throughout their service life. For example, servicedcompressor blades of a gas turbine engine show erosion, defects, and/orcracks after long term use. Specifically, for example, such blades aresubject to significant stresses which inevitably cause blades to wearover time, particularly near the tip of the blade. For example, bladetips are susceptible to wear or damage from friction or rubbing betweenthe blade tips and shrouds, from chemical degradation or oxidation fromhot gasses, from fatigue caused by cyclic loading and unloading, fromdiffusion creep of crystalline lattices, etc.

Notably, worn or damaged blades may result in machine failure orperformance degradation if not corrected. Specifically, such blades maycause a turbomachine to exhibit reduced operating efficiency as gapsbetween blade tips and turbine shrouds may allow gasses to leak throughthe turbine stages without being converted to mechanical energy. Whenefficiency drops below specified levels, the turbomachine is typicallyremoved from service for overhaul and refurbishment. Moreover, weakenedblades may result in complete fractures and catastrophic failure of theengine.

As a result, compressor blades for a gas turbine engine are typicallythe target of frequent inspections, repairs, or replacements. It isfrequently very expensive to replace such blades altogether, however,some can be repaired for extended lifetime at relatively low cost (ascompared to replacement with entirely new blades). Nevertheless,existing repair processes tend to be labor intensive and time consuming.

For example, a traditional compressor blade tip repair process uses awelding/cladding technique where repair materials are supplied, ineither powder or wire form, to the blade tips. The repair materials aremelted by focused power source (e.g., laser, e-beam, plasma arc, etc.)and bonded to blade tips. However, blades repaired with suchwelding/cladding technique need tedious post-processing to achieve thetarget geometry and surface finish. Specifically, due to the bulkyfeature size of the welding/cladding repair joint, the repaired bladesrequire heavy machining to remove the extra materials on the tip, andfurther require a secondary polishing process to achieve a targetsurface finish. Notably, such a process is performed on a single bladeat a time, is very labor intensive and tedious, and results in verylarge overall labor costs for a single repair.

Alternatively, other direct-energy-deposition (DED) methods may be usedfor blade repair, e.g., such as cold spray, which directs high-speedmetal powders to bombard the target or base component such that thepowders deform and deposit on the base component. However, none of theseDED methods are suitable for batch processing or for repairing a largenumber of components in a time efficient manner, thus providing littleor no business value.

Accordingly, novel systems and methods have been developed and arepresented herein for repairing or rebuilding worn compressor blades (orany other components) using a powder bed additive manufacturing process.Specifically, such a repair process generally includes removing the wornportion of each of a plurality of compressor blades, positioning theplurality of compressor blades on a build platform of an additivemanufacturing machine, determining the precise location of each bladetip, and printing repair segments directly onto the blade tips, layer bylayer, until the compressor blades reach their original dimensions oranother suitable target size and shape.

One of the key challenges with such a novel additive manufacturing DMLMrepair procedures described herein relates to loading, unloading, andhandling additive powder which is used to fill the powder bed. In thisregard, to perform a repair process on the tip of a blade, the powderbed must first be loaded with additive powder to the height of the bladetips. Such a process generally includes manually loading the additivepowder, which is time-consuming and can also be costly, especially forcomponents with large dimensions in the build orientation, e.g., theheight of the blades. Moreover, any unpacked additive powder mightcollapse during printing, resulting in failure of recoating. Inaddition, filling the entire volume of the powder bed which is notfilled by components to be repaired can require a large volume of powderwhich must be added prior to printing, removed after printing, andfiltered or screened prior to reuse during a subsequent additivemanufacturing process.

Accordingly, a system and method for repairing components using anadditive manufacturing machine would be useful. More particularly, anadditive manufacturing machine including features for minimizing powderusage during a powder bed additive manufacturing process would beparticularly beneficial.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one exemplary embodiment of the present disclosure, an additivemanufacturing machine for repairing a component is provided. Theadditive manufacturing machine includes a build platform configured forsupporting a component and being movable along a build direction, apowder dispensing assembly for selectively depositing additive powderover the build platform, and a powder seal assembly. The powder sealassembly includes a powder support plate positioned above the buildplatform, the powder support plate defining an aperture for receivingthe component without contacting the component and a clamping mechanismmovable relative to the powder support plate, a void being definedbetween the clamping mechanism and the powder support plate proximatethe aperture. The powder seal assembly further includes a resilientsealing element positioned within the void and extending substantiallyaround the aperture and an actuating mechanism for moving the clampingmechanism toward the powder support plate to deform the resilientsealing element until the resilient sealing element contacts and forms aseal with the component.

In another exemplary aspect of the present disclosure, a method ofmounting a component in an additive manufacturing machine is provided.The method includes mounting the component on a build platform, thebuild platform being movable along a build direction. The method furtherincludes positioning a powder support plate above the build platform,the powder support plate defining an aperture through which thecomponent is received without contacting the powder support plate anddeforming a resilient sealing element operably coupled to the powdersupport plate substantially around the aperture using an actuatingmechanism to contact and seal against the component.

In yet another exemplary aspect of the present disclosure, a powder sealassembly for use in an additive manufacturing machine for repairing acomponent is provided. The powder seal assembly includes a powdersupport plate positioned above a build platform of the additivemanufacturing machine, the powder support plate defining an aperture forreceiving the component without contacting the component and a clampingmechanism movable relative to the powder support plate, a void beingdefined between the clamping mechanism and the powder support plateproximate the aperture. The powder seal assembly further includes aresilient sealing element positioned within the void and around theaperture and an actuating mechanism for moving the clamping mechanismtoward the powder support plate to deform the resilient sealing elementuntil the resilient sealing element contacts and forms a seal with thecomponent.

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures.

FIG. 1 shows a schematic representation of an additive repair systemthat may be used for repairing or rebuilding components according to anexemplary embodiment of the present subject matter.

FIG. 2 depicts certain components of a controller according to exampleembodiments of the present subject matter.

FIG. 3 shows a schematic view of an additive manufacturing machine thatmay be used as part of the exemplary additive repair system of FIG. 1according to an exemplary embodiment of the present subject matter.

FIG. 4 shows a close-up schematic view of a build platform of theexemplary additive manufacturing machine of FIG. 3 according to anexemplary embodiment of the present subject matter.

FIG. 5 is a schematic cross sectional view of a powder seal assemblythat may be used with the exemplary additive manufacturing machine ofFIG. 3 in an un-deformed or unclamped position according to an exemplaryembodiment of the present subject matter.

FIG. 6 is a schematic cross sectional view of the exemplary powder sealassembly of FIG. 5 in a sealing position according to an exemplaryembodiment of the present subject matter.

FIG. 7 is a schematic cross sectional view of the exemplary powder sealassembly of FIG. 5 in a sealing position with a layer of additive powderdeposited according to an exemplary embodiment of the present subjectmatter.

FIG. 8 is a schematic top view of a powder seal assembly that may beused with the exemplary additive manufacturing machine of FIG. 3 in anun-deformed or unclamped position according to an exemplary embodimentof the present subject matter.

FIG. 9 is a schematic cross sectional view of the exemplary powder sealassembly of FIG. 5 according to an exemplary embodiment of the presentsubject matter.

FIG. 10 is a method of mounting a plurality of components in a powderbed additive manufacturing machine according to an exemplary embodimentof the present subject matter.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the accompanyingdrawings. Each example is provided by way of explanation of theinvention, not limitation of the invention. In fact, it will be apparentto those skilled in the art that various configurations, modifications,and variations can be made in the present invention without departingfrom the scope or spirit of the invention. For instance, featuresillustrated or described as part of one embodiment can be used withanother embodiment to yield a still further embodiment. Thus, it isintended that the present invention covers such modifications andvariations as come within the scope of the appended claims and theirequivalents.

As used herein, the terms “first,” “second,” and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.In addition, the terms “upstream” and “downstream” refer to the relativedirection with respect to the motion of an object or a flow of fluid.For example, “upstream” refers to the direction from which the objecthas moved or fluid has flowed, and “downstream” refers to the directionto which the object is moving or the fluid is flowing. Furthermore, asused herein, terms of approximation, such as “approximately,”“substantially,” or “about,” refer to being within a ten percent marginof error.

Aspects of the present subject matter are directed to a system andmethod for repairing one or more components using an additivemanufacturing process. The method includes securing the components in atooling assembly such that a repair surface of each component ispositioned within a single build plane, determining a repair toolpathcorresponding to the repair surface of each component using a visionsystem, depositing a layer of additive powder over the repair surface ofeach component using a powder dispensing assembly, and selectivelyirradiating the layer of additive powder along the repair toolpath tofuse the layer of additive powder onto the repair surface of eachcomponent.

Specifically, aspects of the present subject matter provide a powderseal assembly including a powder support plate positioned above thebuild platform and defining an aperture for receiving the componentwithout contacting the component. A clamping mechanism is movablerelative to the powder support plate and defines a void for receiving aresilient sealing element around the aperture. An actuating mechanism,such as bolts or a linear actuator, moves the clamping mechanism towardthe powder support plate to deform the resilient sealing element untilthe resilient sealing element contacts and forms a seal with thecomponent, thereby forming a support surface above the build platformupon which additive powder may be deposited. In this manner, a tip ofthe component or a plurality of components may be repaired withoutrequiring large amounts of additive powder.

As described in detail below, exemplary embodiments of the presentsubject matter involve the use of additive manufacturing machines ormethods. As used herein, the terms “additively manufactured” or“additive manufacturing techniques or processes” refer generally tomanufacturing processes wherein successive layers of material(s) areprovided on each other to “build-up,” layer-by-layer, athree-dimensional component. The successive layers generally fusetogether to form a monolithic component which may have a variety ofintegral sub-components.

Although additive manufacturing technology is described herein asenabling fabrication of complex objects by building objectspoint-by-point, layer-by-layer, typically in a vertical direction, othermethods of fabrication are possible and within the scope of the presentsubject matter. For example, although the discussion herein refers tothe addition of material to form successive layers, one skilled in theart will appreciate that the methods and structures disclosed herein maybe practiced with any additive manufacturing technique or manufacturingtechnology. For example, embodiments of the present invention may uselayer-additive processes, layer-subtractive processes, or hybridprocesses.

Suitable additive manufacturing techniques in accordance with thepresent disclosure include, for example, Fused Deposition Modeling(FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjetsand laserjets, Sterolithography (SLA), Direct Selective Laser Sintering(DSLS), Electron Beam Sintering (EBS), Electron Beam Melting (EBM),Laser Engineered Net Shaping (LENS), Laser Net Shape Manufacturing(LNSM), Direct Metal Deposition (DMD), Digital Light Processing (DLP),Direct Selective Laser Melting (DSLM), Selective Laser Melting (SLM),Direct Metal Laser Melting (DMLM), and other known processes.

In addition to using a direct metal laser sintering (DMLS) or directmetal laser melting (DMLM) process where an energy source is used toselectively sinter or melt portions of a layer of powder, it should beappreciated that according to alternative embodiments, the additivemanufacturing process may be a “binder jetting” process. In this regard,binder jetting involves successively depositing layers of additivepowder in a similar manner as described above. However, instead of usingan energy source to generate an energy beam to selectively melt or fusethe additive powders, binder jetting involves selectively depositing aliquid binding agent onto each layer of powder. The liquid binding agentmay be, for example, a photo-curable polymer or another liquid bondingagent. Other suitable additive manufacturing methods and variants areintended to be within the scope of the present subject matter.

The additive manufacturing processes described herein may be used forforming components using any suitable material. For example, thematerial may be plastic, metal, concrete, ceramic, polymer, epoxy,photopolymer resin, or any other suitable material that may be in solid,liquid, powder, sheet material, wire, or any other suitable form. Morespecifically, according to exemplary embodiments of the present subjectmatter, the additively manufactured components described herein may beformed in part, in whole, or in some combination of materials includingbut not limited to pure metals, nickel alloys, chrome alloys, titanium,titanium alloys, magnesium, magnesium alloys, aluminum, aluminum alloys,iron, iron alloys, stainless steel, and nickel or cobalt basedsuperalloys (e.g., those available under the name Inconel® availablefrom Special Metals Corporation). These materials are examples ofmaterials suitable for use in the additive manufacturing processesdescribed herein, and may be generally referred to as “additivematerials.”

In addition, one skilled in the art will appreciate that a variety ofmaterials and methods for bonding those materials may be used and arecontemplated as within the scope of the present disclosure. As usedherein, references to “fusing” may refer to any suitable process forcreating a bonded layer of any of the above materials. For example, ifan object is made from polymer, fusing may refer to creating a thermosetbond between polymer materials. If the object is epoxy, the bond may beformed by a crosslinking process. If the material is ceramic, the bondmay be formed by a sintering process. If the material is powdered metal,the bond may be formed by a melting or sintering process. One skilled inthe art will appreciate that other methods of fusing materials to make acomponent by additive manufacturing are possible, and the presentlydisclosed subject matter may be practiced with those methods.

In addition, the additive manufacturing process disclosed herein allowsa single component to be formed from multiple materials. Thus, thecomponents described herein may be formed from any suitable mixtures ofthe above materials. For example, a component may include multiplelayers, segments, or parts that are formed using different materials,processes, and/or on different additive manufacturing machines. In thismanner, components may be constructed which have different materials andmaterial properties for meeting the demands of any particularapplication. In addition, although the components described herein areconstructed entirely by additive manufacturing processes, it should beappreciated that in alternate embodiments, all or a portion of thesecomponents may be formed via casting, machining, and/or any othersuitable manufacturing process. Indeed, any suitable combination ofmaterials and manufacturing methods may be used to form thesecomponents.

An exemplary additive manufacturing process will now be described.Additive manufacturing processes fabricate components usingthree-dimensional (3D) information, for example a three-dimensionalcomputer model, of the component. Accordingly, a three-dimensionaldesign model of the component may be defined prior to manufacturing. Inthis regard, a model or prototype of the component may be scanned todetermine the three-dimensional information of the component. As anotherexample, a model of the component may be constructed using a suitablecomputer aided design (CAD) program to define the three-dimensionaldesign model of the component.

The design model may include 3D numeric coordinates of the entireconfiguration of the component including both external and internalsurfaces of the component. For example, the design model may define thebody, the surface, and/or internal passageways such as openings, supportstructures, etc. In one exemplary embodiment, the three-dimensionaldesign model is converted into a plurality of slices or segments, e.g.,along a central (e.g., vertical) axis of the component or any othersuitable axis. Each slice may define a thin cross section of thecomponent for a predetermined height of the slice. The plurality ofsuccessive cross-sectional slices together form the 3D component. Thecomponent is then “built-up” slice-by-slice, or layer-by-layer, untilfinished.

In this manner, the components described herein may be fabricated usingthe additive process, or more specifically each layer is successivelyformed, e.g., by fusing or polymerizing a plastic using laser energy orheat or by sintering or melting metal powder. For example, a particulartype of additive manufacturing process may use an energy beam, forexample, an electron beam or electromagnetic radiation such as a laserbeam, to sinter or melt a powder material. Any suitable laser and laserparameters may be used, including considerations with respect to power,laser beam spot size, and scanning velocity. The build material may beformed by any suitable powder or material selected for enhancedstrength, durability, and useful life, particularly at hightemperatures.

Each successive layer may be, for example, between about 10 μm and 200μm, although the thickness may be selected based on any number ofparameters and may be any suitable size according to alternativeembodiments. Therefore, utilizing the additive formation methodsdescribed above, the components described herein may have cross sectionsas thin as one thickness of an associated powder layer, e.g., 10 μm,utilized during the additive formation process.

In addition, utilizing an additive process, the surface finish andfeatures of the components may vary as need depending on theapplication. For example, the surface finish may be adjusted (e.g., madesmoother or rougher) by selecting appropriate laser scan parameters(e.g., laser power, scan speed, laser focal spot size, etc.) during theadditive process, especially in the periphery of a cross-sectional layerwhich corresponds to the part surface. For example, a rougher finish maybe achieved by increasing laser scan speed or decreasing the size of themelt pool formed, and a smoother finish may be achieved by decreasinglaser scan speed or increasing the size of the melt pool formed. Thescanning pattern and/or laser power can also be changed to change thesurface finish in a selected area.

After fabrication of the component is complete, various post-processingprocedures may be applied to the component. For example, post processingprocedures may include removal of excess powder by, for example, blowingor vacuuming. Other post processing procedures may include a stressrelief process. Additionally, thermal, mechanical, and/or chemical postprocessing procedures can be used to finish the part to achieve adesired strength, surface finish, and other component properties orfeatures.

Notably, in exemplary embodiments, several aspects and features of thepresent subject matter were previously not possible due to manufacturingrestraints. However, the present inventors have advantageously utilizedcurrent advances in additive manufacturing techniques to improve variouscomponents and the method of additively manufacturing such components.While the present disclosure is not limited to the use of additivemanufacturing to form these components generally, additive manufacturingdoes provide a variety of manufacturing advantages, including ease ofmanufacturing, reduced cost, greater accuracy, etc.

Also, the additive manufacturing methods described above enable muchmore complex and intricate shapes and contours of the componentsdescribed herein to be formed with a very high level of precision. Forexample, such components may include thin additively manufacturedlayers, cross sectional features, and component contours. In addition,the additive manufacturing process enables the manufacture of a singlecomponent having different materials such that different portions of thecomponent may exhibit different performance characteristics. Thesuccessive, additive nature of the manufacturing process enables theconstruction of these novel features. As a result, components formedusing the methods described herein may exhibit improved performance andreliability.

Referring now to FIG. 1, an exemplary additive repair system 50 will bedescribed according to an exemplary embodiment of the present subjectmatter. As illustrated, additive repair system 50 generally includes atooling fixture or assembly 52, a material removal assembly 54, a visionsystem 56, a user interface panel 58, and an additive manufacturingmachine or system 100. Furthermore, a system controller 60 may beoperably coupled with some or all parts of additive repair system 50 forfacilitating system operation. For example, system controller 60 may beoperably coupled to user interface panel 58 to permit operatorcommunication with additive repair system 50, e.g., to input commands,upload printing toolpaths or CAD models, initiating operating cycles,etc. Controller 60 may further be in communication with vision system 56for receiving imaging data and with AM machine 100 for performing aprinting process.

According to exemplary embodiments, tooling assembly 52 is generallyconfigured for supporting a plurality of components in a desiredposition and orientation. According to exemplary embodiments, toolingassembly 52 supports twenty (20) high pressure compressor blades 70during an additive manufacturing repair process. Specifically, theadditive manufacturing process may be a powder bed fusion process (e.g.,a DMLM or DMLS process as described above). Although the repairedcomponents are illustrated herein as compressor blades 70 of a gasturbine engine, it should be appreciated that any other suitablecomponent may be repaired, such as turbine blades, other airfoils, orcomponents from other machines. In order to achieve proper recoating andto facilitate the printing process, it may be desirable to position allblades 70 in the same orientation and at the same height such that arepair surface 72 of each blade is in a single build plane. Toolingassembly 52 is a fixture intended to secure blades 70 in such desiredposition and orientation.

Material removal assembly 54 may include a machine or device configuredfor grinding, machining, brushing, etching, polishing, wire electricaldischarge machining (EDM), cutting, or otherwise substantively modifyinga component, e.g., by subtractive modification or material removal. Forexample, material removal assembly 54 may include a belt grinder, a discgrinder, or any other grinding or abrasive mechanism. According to anexemplary embodiment, material removal assembly 54 may be configured forremoving material from a tip of each blade 70 to obtain a desirablerepair surface 72. For example, as explained briefly above, materialremoval assembly 54 may remove at least a portion of blades 70 that hasbeen worn or damaged, e.g., which may include microcracks, pits,abrasions, defects, foreign material, depositions, imperfections, andthe like. According to an exemplary embodiment, each blade 70 isprepared using material removal assembly 54 to achieve the desiredrepair surface 72, after which the blades 70 are all mounted in toolingassembly 52 and leveled appropriately. However, according to alternativeembodiments, material removal assembly 54 may grind each blade 70 as itis fixed in position in tooling assembly 52.

After the blades are prepared, vision system 56 may be used to obtain animage or digital representation of the precise position and coordinatesof each blade 70 positioned in tooling assembly 52. In this regard,according to exemplary embodiments, vision system 56 may include anysuitable camera or cameras 80, scanners, imaging devices, or othermachine vision device that may be operably configured to obtain imagedata that includes a digital representation of one or more fields ofview. Such a digital representation may sometimes be referred to as adigital image or an image; however, it will be appreciated that thepresent disclosure may be practiced without rendering such a digitalrepresentation in human-visible form. Nevertheless, in some embodiments,a human-visible image corresponding to a field of view may be displayedon the user interface 58 based at least in part on such a digitalrepresentation of one or more fields of view.

Vision system 56 allows the additive repair system 50 to obtaininformation pertaining to one or more blades 70 onto which one or morerepair segments 74 (see FIG. 4) may be respectively additively printed.In particular, the vision system 56 allows the one or more blades 70 tobe located and defined so that the additive manufacturing machine 100may be instructed to print one or more repair segments 74 on acorresponding one or more blades 70 with suitably high accuracy andprecision. According to an exemplary embodiment, the one or more blades70 may be secured to tooling assembly 52, a mounting plate, a buildplatform, or any other fixture with repair surface 72 of the respectiveblades 70 aligned to a single build plane 82.

The one or more cameras 80 of the vision system 56 may be configured toobtain two-dimensional or three-dimensional image data, including atwo-dimensional digital representation of a field of view and/or athree-dimensional digital representation of a field of view. Alignmentof the repair surface 72 of the blades 70 with the build plane 82 allowsthe one or more cameras 80 to obtain higher quality images. For example,the one or more cameras 80 may have a focal length adjusted oradjustable to the build plane 82. With the repair surface 72 of one ormore blades 70 aligned to the build plane 82, the one or more camerasmay readily obtain digital images of the repair surface 72.

The one or more cameras 80 may include a field of view that encompassesall or a portion of the one or more blades 70 secured to the toolingassembly 52. For example, a single field of view may be wide enough toencompass a plurality of components, such as each of the plurality ofblades 70 secured to tooling assembly 52. Alternatively, a field of viewmay more narrowly focus on an individual blade 70 such that digitalrepresentations of respective blades 70 are obtained separately. It willbe appreciated that separately obtained digital images may be stitchedtogether to obtain a digital representation of a plurality of componentsor blades 70. In some embodiments, the camera 80 may include acollimated lens configured to provide a flat focal plane, such thatblades 70 or portions thereof located towards the periphery of the fieldof view are not distorted. Additionally, or in the alternative, thevision system 56 may utilize a distortion correction algorithm toaddress any such distortion.

Image data obtained by the vision system 56, including a digitalrepresentation of one or more blades 70 may be transmitted to a controlsystem, such as controller 60. Controller 60 may be configured todetermine a repair surface 72 of each of a plurality of blades 70 fromone or more digital representations of one or more fields of view havingbeen captured by the vision system 56, and then determine one or morecoordinates of the repair surface 72 of respective ones of the pluralityof blades 70. Based on the one or more digital representations,controller 60 may generate one or more print commands (e.g.,corresponding to one or more repair toolpaths, e.g., the path of a laserfocal point), which may be transmitted to an additive manufacturingmachine 100 such that the additive manufacturing machine 100 mayadditively print a plurality of repair segments 74 on respective ones ofthe plurality of blades 70. The one or more print commands may beconfigured to additively print a plurality of repair segments 74 witheach respective one of the plurality of repair segments 74 being locatedon the repair surface 72 of a corresponding blade 70.

Each of the components and subsystems of additive repair system 50 aredescribed herein in the context of an additive blade repair process.However, it should be appreciated that aspects of the present subjectmatter may be used to repair or rebuild any suitable components. Thepresent subject matter is not intended to be limited to the specificrepair process described. In addition, FIG. 1 illustrates each of thesystems as being distinct or separate from each other and implies theprocess steps should be performed in a particular order, however, itshould be appreciated that these subsystems may be integrated into asingle machine, process steps may be swapped, and other changes to thebuild process may be implemented while remaining within the scope of thepresent subject matter.

For example, vision system 56 and additive manufacturing machine 100 maybe provided as a single, integrated unit or as separate stand-aloneunits. In addition, controller 60 may include one or more controlsystems. For example, a single controller 60 may be operably configuredto control operations of the vision system 56 and the additivemanufacturing machine 100, or separate controllers 60 may be operablyconfigured to respectively control the vision system 56 and the additivemanufacturing machine 100.

Operation of additive repair system 50, vision system 56, and AM machine100 may be controlled by electromechanical switches or by a processingdevice or controller 60 (see, e.g., FIGS. 1 and 2). According toexemplary embodiments, controller 60 may be operatively coupled to userinterface panel 58 for user manipulation, e.g., to control the operationof various components of AM machine 100 or system 50. In this regard,controller 60 may operably couple all systems and subsystems withinadditive repair system 50 to permit communication and data transfertherebetween. In this manner, controller 60 may be generally configuredfor operating additive repair system 50 or performing one or more of themethods described herein.

FIG. 2 depicts certain components of controller 60 according to exampleembodiments of the present disclosure. Controller 60 can include one ormore computing device(s) 60A which may be used to implement methods asdescribed herein. Computing device(s) 60A can include one or moreprocessor(s) 60B and one or more memory device(s) 60C. The one or moreprocessor(s) 60B can include any suitable processing device, such as amicroprocessor, microcontroller, integrated circuit, an applicationspecific integrated circuit (ASIC), a digital signal processor (DSP), afield-programmable gate array (FPGA), logic device, one or more centralprocessing units (CPUs), graphics processing units (GPUs) (e.g.,dedicated to efficiently rendering images), processing units performingother specialized calculations, etc. The memory device(s) 60C caninclude one or more non-transitory computer-readable storage medium(s),such as RAM, ROM, EEPROM, EPROM, flash memory devices, magnetic disks,etc., and/or combinations thereof.

The memory device(s) 60C can include one or more computer-readable mediaand can store information accessible by the one or more processor(s)60B, including instructions 60D that can be executed by the one or moreprocessor(s) 60B. For instance, the memory device(s) 60C can storeinstructions 60D for running one or more software applications,displaying a user interface, receiving user input, processing userinput, etc. In some implementations, the instructions 60D can beexecuted by the one or more processor(s) 60B to cause the one or moreprocessor(s) 60B to perform operations, e.g., such as one or moreportions of methods described herein. The instructions 60D can besoftware written in any suitable programming language or can beimplemented in hardware. Additionally, and/or alternatively, theinstructions 60D can be executed in logically and/or virtually separatethreads on processor(s) 60B.

The one or more memory device(s) 60C can also store data 60E that can beretrieved, manipulated, created, or stored by the one or moreprocessor(s) 60B. The data 60E can include, for instance, data tofacilitate performance of methods described herein. The data 60E can bestored in one or more database(s). The one or more database(s) can beconnected to controller 60 by a high bandwidth LAN or WAN, or can alsobe connected to controller through one or more network(s) (not shown).The one or more database(s) can be split up so that they are located inmultiple locales. In some implementations, the data 60E can be receivedfrom another device.

The computing device(s) 60A can also include a communication module orinterface 60F used to communicate with one or more other component(s) ofcontroller 60 or additive manufacturing machine 100 over the network(s).The communication interface 60F can include any suitable components forinterfacing with one or more network(s), including for example,transmitters, receivers, ports, controllers, antennas, or other suitablecomponents.

Referring now to FIG. 3, an exemplary laser powder bed fusion system,such as a DMLS or DMLM system 100, will be described according to anexemplary embodiment. Specifically, AM system 100 is described herein asbeing used to build or repair blades 70. It should be appreciated thatblades 70 are only an exemplary component to be built or repaired andare used primarily to facilitate description of the operation of AMmachine 100. The present subject matter is not intended to be limited inthis regard, but instead AM machine 100 may be used for printing repairsegments on any suitable plurality of components.

As illustrated, AM system 100 generally defines a vertical direction Vor Z-direction, a lateral direction L or X-direction, and a transversedirection T or Y-direction (see FIG. 1), each of which is mutuallyperpendicular, such that an orthogonal coordinate system is generallydefined. As illustrated, system 100 includes a fixed enclosure or buildarea 102 which provides a contaminant-free and controlled environmentfor performing an additive manufacturing process. In this regard, forexample, enclosure 102 serves to isolate and protect the othercomponents of the system 100. In addition, enclosure 102 may be providedwith a flow of an appropriate shielding gas, such as nitrogen, argon, oranother suitable gas or gas mixture. In this regard, enclosure 102 maydefine a gas inlet port 104 and a gas outlet port 106 for receiving aflow of gas to create a static pressurized volume or a dynamic flow ofgas.

Enclosure 102 may generally contain some or all components of AM system100. According to an exemplary embodiment, AM system 100 generallyincludes a table 110, a powder supply 112, a scraper or recoatermechanism 114, an overflow container or reservoir 116, and a buildplatform 118 positioned within enclosure 102. In addition, an energysource 120 generates an energy beam 122 and a beam steering apparatus124 directs energy beam 122 to facilitate the AM process as described inmore detail below. Each of these components will be described in moredetail below.

According to the illustrated embodiment, table 110 is a rigid structuredefining a planar build surface 130. In addition, planar build surface130 defines a build opening 132 through which build chamber 134 may beaccessed. More specifically, according to the illustrated embodiment,build chamber 134 is defined at least in part by vertical walls 136 andbuild platform 118. Notably, build platform 118 is movable along a builddirection 138 relative to build surface 130. More specifically, builddirection 138 may correspond to the vertical direction V, such thatmoving build platform 118 down increases the height of the part beingprinted and the build chamber 134. In addition, build surface 130defines a supply opening 140 through which additive powder 142 may besupplied from powder supply 112 and a reservoir opening 144 throughwhich excess additive powder 142 may pass into overflow reservoir 116.Collected additive powders may optionally be treated to sieve out loose,agglomerated particles before re-use.

Powder supply 112 generally includes an additive powder supply container150 which generally contains a volume of additive powder 142 sufficientfor some or all of the additive manufacturing process for a specificpart or parts. In addition, powder supply 112 includes a supply platform152, which is a plate-like structure that is movable along the verticaldirection within powder supply container 150. More specifically, asupply actuator 154 vertically supports supply platform 152 andselectively moves it up and down during the additive manufacturingprocess.

AM system 100 further includes recoater mechanism 114, which is a rigid,laterally-elongated structure that lies proximate build surface 130. Forexample, recoater mechanism 114 may be a hard scraper, a soft squeegee,or a roller. Recoater mechanism 114 is operably coupled to a recoateractuator 160 which is operable to selectively move recoater mechanism114 along build surface 130. In addition, a platform actuator 164 isoperably coupled to build platform 118 and is generally operable formoving build platform 118 along the vertical direction during the buildprocess. Although actuators 154, 160, and 164 are illustrated as beinghydraulic actuators, it should be appreciated that any other type andconfiguration of actuators may be used according to alternativeembodiments, such as pneumatic actuators, hydraulic actuators, ballscrew linear electric actuators, or any other suitable vertical supportmeans. Other configurations are possible and within the scope of thepresent subject matter.

As used herein, “energy source” may be used to refer to any device orsystem of devices configured for directing an energy beam of suitablepower and other operating characteristics towards a layer of additivepowder to sinter, melt, or otherwise fuse a portion of that layer ofadditive powder during the build process. For example, energy source 120may be a laser or any other suitable irradiation emission directingdevice or irradiation device. In this regard, an irradiation or lasersource may originate photons or laser beam irradiation which is directedby the irradiation emission directing device or beam steering apparatus.

According to an exemplary embodiment, beam steering apparatus 124includes one or more mirrors, prisms, lenses, and/or electromagnetsoperably coupled with suitable actuators and arranged to direct andfocus energy beam 122. In this regard, for example, beam steeringapparatus 124 may be a galvanometer scanner that moves or scans thefocal point of the laser beam 122 emitted by energy source 120 acrossthe build surface 130 during the laser melting and sintering processes.In this regard, energy beam 122 can be focused to a desired spot sizeand steered to a desired position in plane coincident with build surface130. The galvanometer scanner in powder bed fusion technologies istypically of a fixed position but the movable mirrors/lenses containedtherein allow various properties of the laser beam to be controlled andadjusted. According to exemplary embodiments, beam steering apparatusmay further include one or more of the following: optical lenses,deflectors, mirrors, beam splitters, telecentric lenses, etc.

It should be appreciated that other types of energy sources 120 may beused which may use an alternative beam steering apparatus 124. Forexample, an electron beam gun or other electron source may be used tooriginate a beam of electrons (e.g., an “e-beam”). The e-beam may bedirected by any suitable irradiation emission directing devicepreferably in a vacuum. When the irradiation source is an electronsource, the irradiation emission directing device may be, for example,an electronic control unit which may include, for example, deflectorcoils, focusing coils, or similar elements. According to still otherembodiments, energy source 120 may include one or more of a laser, anelectron beam, a plasma arc, an electric arc, etc.

Prior to an additive manufacturing process, recoater actuator 160 may belowered to provide a supply of powder 142 of a desired composition (forexample, metallic, ceramic, and/or organic powder) into supply container150. In addition, platform actuator 164 may move build platform 118 toan initial high position, e.g., such that it substantially flush orcoplanar with build surface 130. Build platform 118 is then loweredbelow build surface 130 by a selected layer increment. The layerincrement affects the speed of the additive manufacturing process andthe resolution of a components or parts (e.g., blades 70) beingmanufactured. As an example, the layer increment may be about 10 to 100micrometers (0.0004 to 0.004 in.).

Additive powder is then deposited over the build platform 118 beforebeing fused by energy source 120. Specifically, supply actuator 154 mayraise supply platform 152 to push powder through supply opening 140,exposing it above build surface 130. Recoater mechanism 114 may then bemoved across build surface 130 by recoater actuator 160 to spread theraised additive powder 142 horizontally over build platform 118 (e.g.,at the selected layer increment or thickness). Any excess additivepowder 142 drops through the reservoir opening 144 into the overflowreservoir 116 as recoater mechanism 114 passes from left to right (asshown in FIG. 3). Subsequently, recoater mechanism 114 may be moved backto a starting position.

Therefore, as explained herein and illustrated in FIG. 3, recoatermechanism 114, recoater actuator 160, supply platform 152, and supplyactuator 154 may generally operate to successively deposit layers ofadditive powder 142 or other additive material to facilitate the printprocess. As such, these components may collectively be referred toherein as powder dispensing apparatus, system, or assembly. The leveledadditive powder 142 may be referred to as a “build layer” 172 (see FIG.4) and the exposed upper surface thereof may be referred to as buildsurface 130. When build platform 118 is lowered into build chamber 134during a build process, build chamber 134 and build platform 118collectively surround and support a mass of additive powder 142 alongwith any components (e.g., blades 70) being built. This mass of powderis generally referred to as a “powder bed,” and this specific categoryof additive manufacturing process may be referred to as a “powder bedprocess.”

During the additive manufacturing process, the directed energy source120 is used to melt a two-dimensional cross-section or layer of thecomponent (e.g., blades 70) being built. More specifically, energy beam122 is emitted from energy source 120 and beam steering apparatus 124 isused to steer the focal point 174 of energy beam 122 over the exposedpowder surface in an appropriate pattern (referred to herein as a“toolpath”). A small portion of exposed layer of the additive powder 142surrounding focal point 174, referred to herein as a “weld pool” or“melt pool” or “heat effected zone” 176 (best seen in FIG. 4) is heatedby energy beam 122 to a temperature allowing it to sinter or melt, flow,and consolidate. As an example, melt pool 176 may be on the order of 100micrometers (0.004 in.) wide. This step may be referred to as fusingadditive powder 142.

Build platform 118 is moved vertically downward by the layer increment,and another layer of additive powder 142 is applied in a similarthickness. The directed energy source 120 again emits energy beam 122and beam steering apparatus 124 is used to steer the focal point 174 ofenergy beam 122 over the exposed powder surface in an appropriatepattern. The exposed layer of additive powder 142 is heated by energybeam 122 to a temperature allowing it to sinter or melt, flow, andconsolidate both within the top layer and with the lower,previously-solidified layer. This cycle of moving build platform 118,applying additive powder 142, and then directed energy beam 122 to meltadditive powder 142 is repeated until the entire component (e.g., blades70) is complete.

Referring again briefly to FIG. 1, tooling assembly 52 is generallyconfigured for receiving one or more components, e.g., shown here asblades 70, and securely mounting such components for a subsequentadditive manufacturing process. Specifically, tooling assembly 52 maysecure each of the plurality of blades 70 in a desired position andorientation relative to AM machine 100. In this regard, as used herein,the “position” of a blade 70 may refer to the coordinates of a centroidof blade 70 in the X-Y plane. In addition, the “orientation” of a blade70 may refer to an angular position of blade 70 about the Z-direction.In this regard, according to an exemplary embodiment, the orientation ofeach blade 70 may be defined according to the angular position of itschord line (not shown). In this regard, for example, two blades 70 aresaid to have the same “orientation” when their chord lines are parallelto each other.

According to the exemplary embodiment described herein, tooling assembly52 includes a mounting plate 180 which is configured for receivingblades 70 before being positioned at a known location on build platform118. However, it should be appreciated that according to alternativeembodiments build platform 118 may be used directly as a mounting plate.In this regard, for example, mounting plate 180 may be removedaltogether and blades 70 may be positioned, oriented, and secured wheredesired directly on build platform 118.

In addition, tooling assembly 52 is generally configured for supportinga plurality of blades 70 such that the repair surface 72 of each blade70 is positioned within a build plane 82. In this manner, a layer ofadditive powder (e.g., build layer 172) may be deposited over eachrepair surface 72 at a desired thickness for forming a first layer ofrepair segments 74 (FIG. 4) on the tip of each blade 70. Notably,however, due to the height of each blade 70 relative to a height ofrepair segments 74, conventional additive manufacturing processesrequire a substantial amount of additive powder 142. Specifically, asubstantial volume of additive powder 142 must typically be providedinto build chamber 134 to form a powder bed that supports the top layerof additive powder or build layer 172.

As explained above, the powder loading process is typically a manualprocess that takes a significant amount of time and can result inrecoating or print errors when pockets or voids collapse within theadditive powder 142. In addition, additive manufacturing machine 100, orbuild platform 118 more specifically, is typically configured for onlysupporting a specific volume or weight of additive powder 142 during thebuild process, thus introducing process limitations when powder bed isfilled with additive powder 142. Finally, even to the extent someunfused additive powder 142 may be reused during subsequent additivemanufacturing processes, such used additive powder 142 must be carefullyscreened, filtered, or otherwise reconditioned prior to reuse. Aspectsof the present subject matter are directed to minimizing the amount ofadditive powder required for an additive repair process as describedherein.

Referring now generally to FIGS. 5 through 9, a powder seal assembly 200that may be used with AM system 100 will be described according to anexemplary embodiment of the present subject matter. For example, powderseal assembly 200 may be a part of tooling assembly 52 as described inrelation to FIG. 1. Because powder seal assembly 200 can be used as partof additive repair system 50, tooling assembly 52, or in AM system 100,like reference numerals may be used in FIGS. 5 through 9 to refer tolike features described with respect to FIGS. 1 through 4.

As illustrated, powder seal assembly 200 may include a powder supportplate 202 that is positioned above build platform 118 and/or mountingplate 180. Powder support plate 202 defines one or more apertures 204which correspond to the components being repaired, e.g., blades 70.Powder support plate 202 is mountable to mounting plate 180 or overbuild platform 118 such that each of the components being repaired ispositioned within or through one of the apertures 204. Specifically,according to an exemplary embodiment, powder support plate 202 definestwenty (20) apertures 204 which correspond in shape, position, andorientation with blades 70 as mounted to mounting plate 180 or buildplatform 118. It should be appreciated that according to alternativeembodiments, powder support plate 202 may define apertures 204corresponding to any other suitable component or components tofacilitate an additive repair process.

Notably, in order to facilitate mounting of powder support plate 202prior to a build and the removal of powder support plate 202 after abuild, it may be desirable to allow some clearance between powdersupport plate 202 and blades 70 when powder support plate 202 is mountedto mounting plate 180. In this regard, apertures 204 may be slightlyoversized such that blades 70 slide into apertures 204 during a mountingprocess without contacting powder support plate 202. Moreover, oversizedapertures 204 may be desirable to tolerate geometry differences amongrepair components (e.g., blades 70), especially near the portion wherethe powder seal may be formed. In this manner, damage to blades 70 andcontamination of repair surface 72 may be avoided.

Specifically, powder seal assembly 200 may define a clearance gap 210between the components (e.g., blades 70) and powder support plate 202when powder support plate 202 is positioned over mounting plate 180 orbuild platform 118. According to the illustrated embodiment, clearancegap 210 defines a width 212 which is substantially constant around anentire perimeter of each blade 70. However, it should be appreciatedthat width 212 need not be uniform, particularly when blades 70 havegeometry differences. For example, according to an exemplary embodiment,clearance gap 210 may have a width 212 of approximately 1 mm all the wayaround the component, e.g., blade 70. According to still otherembodiments, clearance gap 210 may be between about 0.1 and 2millimeters, between about 0.5 and 1.5 millimeters, between about 0.8and 1.2 millimeters, greater than 2 millimeters, or any other widthsuitable to facilitate operation of powder seal assembly 200, asdescribed in more detail below.

In order to facilitate the recoating process, top 214 of powder supportplate 202 is positioned at or below the build plane 82 when positionedover mounting plate 180 or build platform 118. Specifically, forexample, blades 70 may extend above top 214 of powder support plate 202by approximately half a millimeter, 1 mm, or greater in order to preventcontact with a recoater mechanism 114 or to otherwise facilitate aproper recoating of additive powder or the print process. As illustratedschematically in FIGS. 5 through 7, powder support plate 202 may bemounted to mounting plate 180 or build platform 118 by one or morevertical support legs 216. In this manner, the vertical spacing betweenbuild platform 118 and powder support plate 202 is substantially fixed.

Mounting plate 180 and powder support plate 202 may generally be formedfrom any suitable material and may have any suitable shape. According tothe illustrated embodiment, powder support plate 202 may be formed bycasting, machining, or by additive manufacturing, e.g., using AM machine100. In addition, these components are formed from a ceramic or metalmaterial such that they may be reused for multiple repair and rebuildprocesses. Specifically, once blades 70 have been repaired using apowder bed additive manufacturing process as described below, each blade70 may be removed from mounting plate 180 and powder support plate 202may be used to mount and seal different blades 70 in a subsequent repairprocess. According still other embodiments, powder support plate 202 maybe formed from plastic, e.g. via injection molding, or may be formed inany other suitable manner or from any other suitable material.

Referring still to FIGS. 5 through 7, powder seal assembly 200 furtherincludes a clamping mechanism 220 which is movable relative to powdersupport plate 202. In this regard, clamping mechanism 220 is positionedbelow powder support plate 202 and is movable along a build direction138. In addition, a void 222 is defined between clamping mechanism 220and powder support plate 202 proximate to and/or surrounding aperture204. A resilient sealing element 224 is positioned within the void 222such that resilient sealing element 224 surrounds blade 70. Althoughresilient sealing element 224 is illustrated and described herein as acontinuous element that wraps around a perimeter of aperture 204 andcompletely surrounds blades 70, it should be appreciated that amulti-part sealing member may be used according to alternativeembodiments while remaining within the scope of the present subjectmatter.

Powder seal assembly 200 further includes an actuating mechanism 230which is generally configured for moving clamping mechanism 220 towardpowder support plate 202 to deform resilient sealing element 224 untilresilient sealing element 224 contacts and forms a seal with thecomponent being repaired, e.g., blades 70. In this manner, actuatingmechanism 230 is movable between an unclamped or relaxed position whereresilient sealing element 224 is substantially un-deformed within thevoid 222 and a clamped or closed position where clamping mechanism 220is urged toward powder support plate 202 to squeeze resilient sealingelement 224 within void 222 until it deforms and contacts blades 70.

As used herein, resilient sealing element 224 may be used to refer toany deformable member that is positioned around blades 70 and isoperably coupled to powder support plate 202 such that it may bedeformed into contact with blades 70. For example, resilient sealingelement 224 may be an O-ring or an elongated rubber band is positionedwithin and fills voids 222 around each blade 70. Resilient sealingelement 224 may be formed from a deformable elastomer, a polymermaterial, or any other suitably resilient material which may deform andretract to its un-deformed position when clamping mechanism 220 isrelaxed.

Resilient sealing element 224, like powder support plate 202, isdesigned such that clearance is provided between resilient sealingelement 224 and blades 70 (when not deformed). In this regard, resilientsealing element 224 may be positioned entirely within void 222 such thatit does not protrude into apertures 204 when clamping mechanism 220 isin the unclamped position. For example, the clearance between resilientsealing element 224 and blades 70 may be greater than or equal to theclearance gap 210 between powder support plate 202 and blades 70.However, as described above, resilient sealing element 224 is configuredfor deforming to contact and seal against the component, e.g., blades70, prior to a powder dispensing and recoating process.

As used herein, clamping mechanism 220 may generally be any device ormechanism suitable for contacting or engaging resilient sealing element224 to deform resilient sealing element 224. In this regard, forexample, clamping mechanism 220 may be a sealing plate 240 which ispositioned below powder support plate 202 and defines apertures whichcorrespond to and are positioned below apertures 204. For example,apertures 204 in powder support plate 202 and clamping mechanism 220 mayhave an identical size, shape, and orientation. In this manner, powdersupport plate 202 and sealing plate 240, when urged together byactuating mechanism 230, close or minimize the void 222 to deformresilient sealing element 224 and form a seal with blades 70. In thismanner, powder support plate 202 and resilient sealing elements 224define a powder support surface positioned proximate repair surface 72of blades 70 such that significantly less additive powder 142 isrequired to facilitate the printing process.

Referring now briefly to FIG. 9, sealing plate 240 is described in moredetail according to one exemplary embodiment. As illustrated, sealingplate 240 defines a support surface 242 that is angled away from powdersupport plate 202 to define void 222. In this manner, as sealing plate240 is moved toward powder support plate 202, the resilient sealingelement 224 is urged toward aperture 204 by the angled support surface242. It should be appreciated that void 222 may be defined in any othersuitable manner between powder support plate 202 and clamping mechanism220. For example, according to alternative embodiments, powder supportplate 202 and sealing plate 240 are fixed relative to each other and athird mechanism may be positioned therebetween for deforming resilientsealing element 224 when desired. As illustrated in FIG. 9, resilientsealing element 224 is illustrated both the un-deformed state (solidlines) and in the deformed state (dotted lines).

In addition, although clamping mechanism 220 is illustrated as sealingplate 240 which extends substantially across a horizontal plane withinbuild chamber 134, it should be appreciated that clamping mechanism 220could instead be any other suitable device or mechanism positionedaround apertures 204 for deforming resilient sealing element 224. Inthis regard, clamping mechanism 220 could instead be a mechanical clamp,a screw clamp, a hydraulic or pneumatic actuator, or any other device ormechanism suitable for deforming resilient sealing element 224.

As explained above, powder seal assembly 200 includes actuatingmechanism 230 for urging clamping mechanism 220 toward powder supportplate 202. As used herein, “actuating mechanism” is intended to refer toany device or mechanism suitable for moving clamping mechanism 220 orotherwise closing void 222 to deform resilient sealing element 224. Forexample, as shown in FIGS. 5 through 7, clamping mechanism 220 includesa plurality of mechanical fasteners 250 which are passed through powdersupport plate 202 and engage sealing plate 240. Mechanical fasteners 250may be screws, bolts, or any other suitable threaded fastener which mayadjust the distance between powder support plate 202 and sealing plate240. According to still other embodiments, e.g., as shown in FIG. 9,actuating mechanism 230 may be a hydraulic or pneumatic actuator 252,which may be operated by regulating the flow of pressurized air from anair supply source (not shown). According to still other embodiments,actuating mechanism 230 may be a piezoelectric actuator that permitsprecise positioning of sealing plate 240 in response to an electricalinput, another suitable linear actuator, an electric motor actuator,etc.

Notably, according to exemplary embodiments the present subject matter,powder seal assembly 200 may be mounted such that a vertical gap 260 isdefined between the powder support plate 202 and build platform 118 (ormounting plate 180 if used). Specifically, if the components beingrepaired are high pressure compressor blades for a gas turbine engine,vertical gap 260 may be approximately 1.5 inches (e.g., approximately38.1 mm), though any other suitable vertical gap 260 may be definedaccording to alternative embodiments, e.g., depending on the height ofcomponents being repaired. For example, vertical gap 260 may be betweenabout 10 and 70 millimeters, between about 20 and 60 millimeters,between about 30 and 50 millimeters, greater than 70 millimeters, etc.Moreover, powder support plate 202 may be directly supported by and movewith build platform 118 along build direction 138. In this manner, asrepair segments 74 are deposited layer by layer, build platform 118 andpowder support plate 202 may move down along build direction 138 tofacilitate the depositing and recoating of additive powder for asubsequent layer.

Notably, as illustrated in FIGS. 5 through 7, powder support plate 202defines two apertures 204 for receiving two blades 70. However, itshould be appreciated that the schematics shown in these figures areonly used for explaining aspects of the present subject matter.According to alternative embodiments, platform 118 may support less thantwo or more than two components, e.g., blades 70. In addition powdersupport plate 202 may define a plurality of apertures 204 thatcorrespond to the blades 70 and resilient sealing elements 224 that areoperably coupled to powder support plate 202 around each of apertures204. In this manner, clamping mechanism 220 may simultaneously deformthe plurality of resilient sealing elements 224 to engage blades 70 andform a single powder support surface on top 214 of powder support plate202 and the plurality of resilient sealing elements 224.

After powder support plate 202 is positioned over build platform 118 ormounting plate 180 as desired, additive powder 142 may be loaded intopowder bed and a recoating assembly, e.g., such as recoater mechanism114, may spread a layer of additive material (e.g., build layer 172)over top 214 of powder support plate 202 and the repair surfaces 72 ofeach component being repaired, e.g., blades 70.

Notably, use of the additive manufacturing methods described above alongwith powder seal assembly 200 facilitates the use of multiple differentadditive materials, e.g., different compositions of additive powders 142during a single print process. In this regard, for example, the additivepowder 142 used may be a different composition than blades 70 and powdersupport plate 202. Moreover, each layer of additive material may differfrom previously deposited and fused additive layers. In this regard,powder seal assembly 200 may provide for precisely controlled transitionlocations between the two materials, e.g., between blades 70 and buildlayer 172. Using the methods described herein, the additivemanufacturing process may be performed in multiple steps, in one or moreadditive manufacturing machines 100 to achieve repair segments 74 thatmay include a plurality of layers formed from multiple different typesof additive powders having different compositions, physical properties,etc.

Notably, powder seal assembly 200 is generally configured for minimizingthe volume of the powder bed, e.g., by raising the support surface uponwhich additive powder 142 is deposited. In addition, powder supportplate 202 may move vertically along the build direction 138 with buildplatform 118. In this manner, the powder bed and blades 70 can grow,layer by layer, as in a conventional additive manufacturing process,without requiring additive powder 142 to fill the entire build chamber134 along the entire height of the components to be repaired. In thismanner, the process for supplying or loading additive powder 142 intopowder bed is simplified. For example, an operator need only fill buildchamber 134 above powder support plate 202. In this manner, the timerequired to prepare the additive manufacturing machine 100 for the printprocess is reduced, as is the amount of additive powder 142 that must beused and the required time for post processing of blades 70 and additivepowder 142.

Now that the construction and configuration of additive repair system 50has been described according to exemplary embodiments of the presentsubject matter, an exemplary method 300 for mounting a plurality ofcomponents for a repair or rebuild process using an additive repairsystem will be described according to an exemplary embodiment of thepresent subject matter. Method 300 can be used to repair blades 70 usingadditive repair system 50, AM machine 100, and powder seal assembly 200,or to repair any other suitable component using any other suitableadditive manufacturing machine or system. In this regard, for example,controller 60 may be configured for implementing some or all steps ofmethod 300. Further, it should be appreciated that the exemplary method300 is discussed herein only to describe exemplary aspects of thepresent subject matter, and is not intended to be limiting.

Referring now to FIG. 10, method 300 includes, at step 310, mounting acomponent on a build platform of an additive manufacturing machine,wherein the build platform is movable along a build direction. Morespecifically, according to exemplary embodiments, a plurality of blades70 may be mounted with the tip or repair surface 72 upward along thevertical direction V. Instead of filling the entire build chamber 134with additive powder 142 to reach repair surfaces 72 of blades 70,powder seal assembly 200 may be used to create an elevated powdersupport surface for minimizing powder usage.

Specifically, step 320 includes positioning a powder support plate abovethe build platform. The powder support plate defines one or moreapertures through which the components are received without contactingpowder support plate. In this regard, powder support plate 202 definesapertures 204 which correspond to blades 70 in both position andorientation. Step 330 includes positioning a resilient sealing elementaround the aperture. In this regard, as described above, resilientsealing element 220 may be an O-ring positioned within the void 222which surrounds blades 70 and is defined in part by clamping mechanism220 or sealing plate 240.

Step 340 includes deforming the resilient sealing element using anactuating mechanism to contact and seal against the component. In thisregard, and actuating mechanism such as a piezoelectric actuator, amechanical clamp, a hydraulic actuation mechanism, a pneumatic actuationmechanism, or a mechanical fastener may urge sealing plate 240 towardpowder support plate 202 to close void 222 and deform resilient sealingelement 224. In this regard, powder support plate 202 and the deformedresilient sealing elements 224 may define a powder support surface whichis raised above build platform 118 or mounting plate 180.

According to an exemplary embodiment, method 300 may further includeadditively printing repair segments 74 onto repair surfaces 72 of eachblade 70 using AM machine 100. In this regard, step 350 includesdepositing a layer of additive powder over the repair surface of thecomponent using a powder dispensing assembly, the layer of additivepowder being supported at least in part by the powder support plate andthe resilient sealing element. Step 360 includes selectively irradiatingthe layer of additive powder to fuse the layer of additive powder ontothe repair surface of the component. In this manner, an energy sourcemay fuse additive powder onto each blade tip layer by layer until thecomponent is repaired to an original CAD model or to another suitablegeometry.

FIG. 10 depicts an exemplary control method having steps performed in aparticular order for purposes of illustration and discussion. Those ofordinary skill in the art, using the disclosures provided herein, willunderstand that the steps of any of the methods discussed herein can beadapted, rearranged, expanded, omitted, or modified in various wayswithout deviating from the scope of the present disclosure. Moreover,although aspects of the methods are explained using additive repairsystem 50, AM machine 100, and powder seal assembly 200 as an example,it should be appreciated that these methods may be applied to repairingor rebuilding any other number, type, and configuration of componentsusing any suitable powder seal assembly or additive manufacturingmachine or system.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. An additive manufacturing machine for repairing acomponent, the additive manufacturing machine comprising: a buildplatform configured for supporting a component and being movable along abuild direction; a powder dispensing assembly for selectively depositingadditive powder over the build platform; and a powder seal assemblycomprising: a powder support plate positioned above the build platform,the powder support plate defining an aperture for receiving thecomponent without contacting the component; a clamping mechanism movablerelative to the powder support plate, a void being defined between theclamping mechanism and the powder support plate proximate the aperture;a resilient sealing element positioned within the void and extendingsubstantially around the aperture; and an actuating mechanism for movingthe clamping mechanism toward the powder support plate to deform theresilient sealing element until the resilient sealing element contactsand forms a seal with the component.
 2. The additive manufacturingmachine of claim 1, wherein the resilient sealing element is an O-ring.3. The additive manufacturing machine of claim 1, wherein the resilientsealing element is formed from a deformable elastomer or polymermaterial.
 4. The additive manufacturing machine of claim 1, wherein theclamping mechanism comprises: a sealing plate positioned below thepowder support plate.
 5. The additive manufacturing machine of claim 4,wherein the sealing plate extends at least partially around the apertureof the powder support plate such that the component may pass through theaperture without contacting the sealing plate.
 6. The additivemanufacturing machine of claim 4, wherein the sealing plate definessupport surface that is angled away from the powder support plate todefine the void, such that the resilient sealing element is urged towardthe aperture.
 7. The additive manufacturing machine of claim 1, whereinthe actuating mechanism comprises one or more clamping bolts that passthrough the powder support plate and into the sealing plate.
 8. Theadditive manufacturing machine of claim 1, wherein the actuatingmechanism comprises one or more of a piezoelectric actuator, amechanical clamp, a hydraulic actuation mechanism, and a pneumaticactuation mechanism.
 9. The additive manufacturing machine of claim 1,wherein a clearance gap is defined between the powder support plate andthe component around the entire component.
 10. The additivemanufacturing machine of claim 9, wherein the clearance gap is betweenabout 0.5 and 1.5 millimeters.
 11. The additive manufacturing machine ofclaim 1, wherein a vertical gap is defined between the build platformand the powder support plate.
 12. The additive manufacturing machine ofclaim 11, wherein the vertical gap is between about 30 and 50millimeters.
 13. The additive manufacturing machine of claim 1, whereinthe powder seal assembly is supported by the build platform such thatthe powder seal assembly moves with the build platform.
 14. The additivemanufacturing machine of claim 1, wherein the build platform supports aplurality of components, the powder support plate defines a plurality ofapertures corresponding to the plurality of components, and theresilient sealing element is positioned around each of the plurality ofapertures.
 15. The additive manufacturing machine of claim 1, whereinthe component is an airfoil of a gas turbine engine.
 16. A method ofmounting a component in an additive manufacturing machine, the methodcomprising: mounting the component on a build platform, the buildplatform being movable along a build direction; positioning a powdersupport plate above the build platform, the powder support platedefining an aperture through which the component is received withoutcontacting the powder support plate; and deforming a resilient sealingelement operably coupled to the powder support plate substantiallyaround the aperture using an actuating mechanism to contact and sealagainst the component.
 17. The method of claim 16, wherein deforming theresilient sealing element using an actuating mechanism comprises:positioning a clamping mechanism below the powder support plate, theclamping mechanism and the powder support plate defining a voidproximate the aperture for receiving the resilient sealing element; andmoving the clamping mechanism toward the powder support plate to deformthe resilient sealing element.
 18. The method of claim 16, furthercomprising: depositing a layer of additive powder over a repair surfaceof the component using a powder dispensing assembly, the layer ofadditive powder being supported at least in part by the powder supportplate and the resilient sealing element; and selectively irradiating thelayer of additive powder to fuse the layer of additive powder onto therepair surface of the component.
 19. The method of claim 16, wherein thebuild platform supports a plurality of components, the powder supportplate defines a plurality of apertures corresponding to the plurality ofcomponents, and the resilient sealing element is positioned around eachof the plurality of apertures.
 20. A powder seal assembly for use in anadditive manufacturing machine for repairing a component, the powderseal assembly comprising: a powder support plate positioned above abuild platform of the additive manufacturing machine, the powder supportplate defining an aperture for receiving the component withoutcontacting the component; a clamping mechanism movable relative to thepowder support plate, a void being defined between the clampingmechanism and the powder support plate proximate the aperture; aresilient sealing element positioned within the void and around theaperture; and an actuating mechanism for moving the clamping mechanismtoward the powder support plate to deform the resilient sealing elementuntil the resilient sealing element contacts and forms a seal with thecomponent.